In the prior art, when a packet is forwarded, layer two forwarding is guided according to exact matching of a media access control (MAC) address. When the packet is forwarded in Ethernet, the packet is forwarded to all interfaces in an unknown unicast flooding (Flooding) way if a matching MAC entry does not exist, thereby achieving a final effect for sending the packet to a destination.
The basic idea for an Ethernet virtual private network (EVPN) is to learn the MAC address on a control plane by expanding a border gateway protocol (BGP) protocol, thereby realizing a function of layer two VPN (L2VPN). Learning the MAC address on the control plane naturally solves the problems caused by performing MAC address learning on a data plane, such as difficulty to realize multi-homing of customer edge (CE) device, unknown unicast Flooding and address resolution protocol (ARP) broadcasting storm. However, with the development of cloud computing, the scale of a data center is expanding continuously, but the way for the EVPN to learn the MAC address on the control plane needs each provider edge (PE) device to store MAC address tables of all connected VPN sites, which needs very high capacity and performance of the PE device.
However, if a capacity limit is taken into account, and an overall MAC address table is not stored on a network device (for example, a PE device), when the packet is forwarded, the packet may be flooded on all interfaces if a MAC entry matching a destination MAC address of the packet does not exist in the MAC address table, but unnecessary network traffic may therefore be increased.